1. Field of the Invention
The present invention relates to a process for producing crystalline silicon nitride powder suitable for the production of sintered silicon nitride, useful as a superhard heat resistant material.
2. Description of the Prior Art
It is known to produce crystalline silicon nitride powder by heating amorphous silicon nitride powder under an inert or reducing gas atmosphere as disclosed in, for example, U.S. Pat. No. 4,196,178. This process, however, involves disadvantages. That is, the resultant crystalline silicon nitride powder has a low tap density and is difficult to handle, due to the large number of needle crystals formed in the heating step. Therefore, only molded articles having a low bulk density can be obtained.